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c# - How to reverse a StringBuilder

Reverse a StringBuilder content
The StringBuilder class represents a mutable String of characters. The StringBuilder class cannot be inherited. The StringBuilder class represents a String-like object whose value is a mutable sequence of characters.

Although StringBuilder and String both represent sequences of characters, they are implemented differently. The String is an immutable type. So, each operation that appears to modify a String object actually creates a new String.

The following .net c# tutorial code demonstrates how we can reverse a StringBuilder instance. So, in this .net c# tutorial code we will reverse the characters sequence of a StringBuilder object. Such as if a StringBuilder content is ‘red’ then we will reverse its content as ‘der’.

There are no direct methods in the StringBuilder class to reverse the contents sequence of a StringBuilder instance. So at first, we have to convert the StringBuilder object to a String object. The StringBuilder ToString() method converts the value of a StringBuilder to a String.

Next, we will create a Char Array from the converted String object. The String ToCharArray() method copies the characters in this instance to a Unicode character Array. Then we will reverse the Array elements using Array Reverse() method. The Array Reverse() method reverses the order of the elements in a one-dimensional Array or in a portion of the Array.

Next, we will create a new String instance from the reversed Array. The String(Char[]) constructor initializes a new instance of the String class to the Unicode characters indicated in the specified character Array.

Finally, using the StringBuilder Replace() method we will replace the StringBuilder content with reversed String object. The StringBuilder Replace() method replaces all occurrences of a specified character or String in this instance with another specified character or String. In this way, we reverse the StringBuilder contents.
stringbuilder-reverse.aspx

<%@ Page Language="C#" AutoEventWireup="true"%>

<!DOCTYPE html>

<script runat="server"> 
    protected void Button1_Click(object sender, System.EventArgs e)  
    {
        StringBuilder stringb = new StringBuilder();
        stringb.Append("Subdesert Mesite. Purple Gallinule.");

        Label1.Text = stringb.ToString();

        //this section reverse stringbuilder contents.
        string convertedString = stringb.ToString();
        char[] charArray = stringb.ToString().ToCharArray();
        Array.Reverse(charArray);

        string s = new string(charArray);

        stringb.Replace(stringb.ToString(), s);

        Label1.Text += "<br /><br />reversed stringbuilder................ <br />";
        Label1.Text += stringb.ToString();
    }  
</script>  

<html xmlns="http://www.w3.org/1999/xhtml">  
<head id="Head1" runat="server">  
    <title>c# example - stringbuilder reverse</title>  
</head>  
<body>  
    <form id="form1" runat="server">  
    <div>  
        <h2 style="color:MidnightBlue; font-style:italic;">  
            c# example - stringbuilder reverse
        </h2>  
        <hr width="550" align="left" color="Gainsboro" />  
        <br />  
        <asp:Label   
            ID="Label1"   
            runat="server"  
            Font-Size="Large"  
            >  
        </asp:Label>  
        <br /><br /><br />
        <asp:Button   
            ID="Button1"   
            runat="server"   
            Text="stringbuilder reverse"  
            OnClick="Button1_Click"
            Height="40"  
            Font-Bold="true"  
            />  
    </div>  
    </form>  
</body>  
</html>
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